Howling refers to a sharp and raspy sound that appears during the use of a sound pickup device or a pickup (for example, a microphone). Howling occurs because a sound output by a player (for example, a sounder and a horn) is constantly captured by the pickup to return to the pickup and is output after being enlarged by a power amplifier of the player in a repeated process, so as to generate a sound positive feedback phenomenon. An existing howling suppression solution determines whether howling occurs by detecting energy of an output signal, and suppresses the howling based on a result of determination.